1. Field of the Invention
The present invention relates to a conducting carrier, and more specifically, to a conducting carrier of a sand blasting device for removing electrostatic charges generated during a sand blasting process.
2. Description of the Prior Art
Plasma display panels (PDP) have large, wide screens and are thin and light. By utilizing ultraviolet light produced by gas discharge to irradiate fluorescent materials in thousands of display elements, red, green and blue lights can be generated and therefore emitted on the PDP. During the formation a back substrate of the PDP, a plurality of barrier ribs, having shapes of either stripes, cells or other shapes due to product requirement, needs to be formed to define each display element before the fluorescent materials are formed on the substrate, so as to prevent the mixing of different fluorescent materials. The width and height of the barrier ribs respectively range from 50 to 80 xcexcm and from 150 to 220 xcexcm, making the barrier ribs very difficult to be formed. Conventional methods of making barrier ribs include printing, photoresist sand blasting, and additive methods. The photoresist sand blasting method combines a photo etching technology and a sand blasting process to achieve precise patterns of the barrier ribs with smaller sizes, and has therefore become the most popular way of making barrier ribs. However, electrostatic charges frequently produced during the sand blasting process are not easily to be moved, therefore leading to a great impact on the quality of the PDP.
Please refer to FIGS. 1 to 4 of schematic views of making a plurality of barrier ribs 20 of a PDP on a back substrate 10 by using a photoresist sand blasting method according to the prior art. As shown in FIG. 1, a plurality of electrodes 12, a protective layer 14 and a barrier rib material layer 16 are sequentially formed on a glass substrate 11. The protective layer 14 is a dielectric layer employed to cover the surface of the glass substrate 11 and the electrodes 12, so as to prevent the electrodes 12 from being damaged in subsequent sand blasting processes. The barrier rib material layer 16 is a dielectric layer composed of low melting point glass and oxides, such as aluminum oxide. As shown in FIG. 2, a photoresist layer 18 is then formed on a predetermined area of the barrier rib material layer 16 by performing exposure and development processes to define the barrier ribs 20. As shown in FIG. 3, a sand blasting process is performed to remove portions of the barrier rib material 16 not covered by the photoresist layer 18 down to the surface of the protective layer 14. As shown in FIG. 4, the photoresist layer 18 is removed, and the residual barrier rib material layer 16 is baked to form a plurality of barrier ribs 20 at a temperature of higher than 500xc2x0 C. to complete the formation of the barrier ribs 20 of the PDP.
The sand blasting process is performed in a sand blasting device (not shown). Portions of the barrier rib material layer 16 uncovered by the photoresist layer 18 is removed by an abrasive sand jetted on the back substrate 10 against the barrier rib material layer 16. However, electric charges are frequently generated and are therefore accumulated on the surface of the barrier rib material layer 16, causing electrostatic discharge during the sand blasting process. Furthermore, the electric charge can be accumulated on the electrodes 12 under the barrier rib material layer 16. When the accumulated charges increase to a certain amount, tip discharging would occur within a gap (not shown) between two neighboring electrodes. As a result, arcing would occur between electrodes when the finished PDP is turned on, leading to appearance of numerous irregularly black spots on the PDP panel.
Therefore, it is a primary objective of the present invention to provide a conducting carrier for a sand blasting process, so as to remove electrostatic charges during the sand blasting process.
In the preferred embodiment of the present invention, the sand blasting process is performed by utilizing a sand blasting device. The sand blasting device has a base, a passageway installed on the base, and a sand blasting nozzle installed above the passageway. The conducting carrier is mounted on the passageway and is capable of sliding along the passageway. The conducting carrier has a plate for supporting a substrate to be sand blasted, and two electrically conducting clippers respectively installed on a first side and a second side of the plate for fixing the substrate to the plate. Electrostatic charges generated during the sand blasting process are capable of being removed from the surface of the substrate by the clippers.
It is an advantage of the present invention that the conducting carrier is utilized to remove electrostatic charges, and thus prevents accumulation of electrostatic charges in gaps between electrodes on the substrate, enhancing the quality of the substrate.